I don't notice any difference between good quality black pads from various makers and Kool Stop salmon pads. The main advantage to Kool Stop is the pad design for some, not all, pads -- the wedge or plow-tip on some Kool Stop pads makes toe-in easier and helps scrape rims clean in wet and muddy conditions.

My Univega has cantilever brakes. I started out with Kool Stop Eagle 2 (formerly Eagle Claw) salmon. Great pad design. The wedge makes it easy to set toe-in, and scrapes the rims clean in muddy conditions. But it wouldn't clear the fork enough to drop/install an inflated tire. The Eagle 2 pads are really thick.

So I switched the front to Jagwire black 70mm long mountain canti thin line pads, curved to match the rim. And they brake just as well as the Kool Stop salmon, dry, wet or muddy. Cost less too. But like most pads toe-in is a little more trouble -- a zip tie, rubber band, etc., helps set the toe-in angle.

My comfort hybrid errand bike has V-brakes. Kool Stop holders with black pads up front, generic black pads in the rear. They work just as well.